The instant invention relates to a touring, telemark, or cross-country ski binding, comprising a supporting means to offer support in forward, upward and side directions to the front part of an associated shoe, especially a front sole section of the same, on a ski or similar piece of sports equipment, further comprising a retaining means to hold the shoe in the supporting means such that the shoe heel can be raised freely.
Ski bindings of this kind are known in general. Reference is made, for the sake of example, to the applicant""s WO 96/23558. With this known design, the sole is supported in the region of the forward sole end and, therefore, contact between shoe and ski or the like sports equipment will get lost as the heel of the shoe is raised higher. As a consequence, control stability and efficiency in the transfer of force will suffer.
Considerable improvement over this prior art is obtained with bindings designed according to DE 195 17 791 A1 and DE 195 03 397 A1 the origin of which likewise is the applicant of the instant application. Those designs are characterized in that the point of engagement of the retaining means, embodied either by a tensioning cable or a pliable tensioning strap, is located at the sole of the ski shoe in the region of the plantar arch or just ahead thereof in order to hold the shoe in the supporting means. As a result, the shoe heel can be lifted much more easily and higher without compromising ski control and force transfer to the ski.
In the case of the binding according to DE 37 08 838 A1 the shoe is held firmly on the ski by almost its entire front sole. This structure obstructs the free lifting of the heel of the shoe.
Starting from the state of the art as established by the applicant, it is the object of the instant invention to design the binding such that still better allowance will be made for the principles of ergonomics. More specifically, it is an object of the instant invention to adapt the binding even better to the natural course of motion of the foot, as the heel is lifted. It is another object of the invention to achieve great lateral stability and stability of control as well as good transfer of force, at the same time.
One aspect of the invention involves a touring, telemark, or cross-country ski binding. The binding includes a supporting means and a retaining means. The supporting means offer support in forward, upward and side directions to a front part of an associated shoe. The retaining means are connected to the supporting means and hold the shoe in the supporting means such that a heel of the shoe can be raised freely. The retaining means include a clamping means selected from a group including a tension cable and clamping plate. The clamping means is pivotably connected to the supporting means in an area of a metatarsal zone and configured to pivot about an axis located above the lower surface of the front sole of the shoe. The clamping means is configured to engages a front part of the shoe behind the metatarsal zone.
Another aspect of the invention involves a binding for a touring, telemark, or cross-country ski. The binding comprises a supporting portion to offer support to a front part of an associated shoe in a forward, upward and lateral direction with respect to the ski. The binding further comprises a retaining portion for holding the shoe in the supporting portion. The retaining portion comprises a clamping portion pivotably connected to the supporting portion in an area of the metatarsal zone for engaging the shoe at a location rearward of a metatarsal zone of the shoe. The retaining portion permits the metatarsal zone of the shoe to move upward with respect to an upper surface of the ski. The clamping portion is configured to pivot about an axis located above the lower surface of the front sole of the shoe.
As regards the ergonomic course of movement, it is of particular significance that the retaining means comprises a tensioning or clamping means, e.g. in the form of a tensioning cable, strap, or rigid clamping plate, or the like which is connected to the ski or binding or to the casing of the latter, especially pivotably connected, in the area of the metatarsal zone so as to engage the front sole of the shoe behind the metatarsal zone. As the shoe heel is raised, this tensioning or clamping means permits free and unobstructed downward curving of the front sole of the shoe. In this manner the heel of the shoe can be lifted without constraint, while the foot arches downwardly in accordance with the natural roll-off motion when walking. Simultaneously, high lateral stability and stability in controlling the ski as well as good transfer of force to the ski are achieved due to the fact that the sole is attached at the forward sole end, on the one hand, and at the rear end of the front sole, on the other hand. This kind of attachment of the shoe likewise contributes to the substantially unobstructed raising of the heel of the shoe, to be accomplished at relatively little investment of energy. And, above all, the heel can be raised much higher than with conventional cross-country or touring ski bindings equipped with retaining means which act on the heel of the shoe.
The additional attachment of the shoe obtained by a retainer which is effective behind the metatarsal zone improves the stability in controlling the ski without losing the mobility of the shoe to raise the heel. Efficient introduction of force and transfer thereof to the piece of sports equipment are achieved by these means. Moreover, testing has confirmed that when using a binding according to the invention the comfort in moving ranks very high. Since the fixing of the shoe in accordance with the invention conforms to the anatomy, its application causes no complaints and helps save energy.
Advantageous embodiments of the design principle according to the invention are defined herein, as mentioned above. Thus, two basic structures of the retaining means are conceivable. One is characterized in that the retaining means is movable as a whole in longitudinal direction of the shoe from a shoe release position to a shoe holding position and vice versa, serving as a shoe clamping means at the same time. In the case of the alternative design, the retaining means is mounted so as to be stationary in longitudinal direction of the shoe. In this case it comprises a separate tensioning or clamping means which is movable back and forth in longitudinal direction of the shoe. This means may be embodied by a tensioning cable, a strap, or the like to hold the shoe on the associated supporting means.
The retaining means preferably is supported for pivoting movement about an axis extending transversely of the longitudinal direction of the shoe and approximately parallel to the tread, in other words approximately horizontally. Hereby an exact sole bending line is defined at the place of the metatarsal zone. The pivot axis preferably lies at the level of the front sole, especially also below it, so that the angulation of the foot will correspond to the anatomy when the heel is raised.
Another alternative, specifically one of very simple structure, is characterized in that the supporting means comprises a toe iron including wedges which project only over the forward sole end, and the retaining means comprises a tensioning cable coupled to a cocking lever or similar cocking member. The tensioning cable is held for longitudinal displacement at deflector members (e.g. in the form of outwardly and downwardly curved, i.e. downwardly open baffles) which are disposed at the outside of both side jaws of the toe iron. The tensioning cable is deflectable in upward direction when the heel of the shoe is raised. Preferably, two or more cable deflector members each are arranged at the outside of both side jaws of the toe iron, at different levels and/or different longitudinal locations, whereby the position in longitudinal direction and/or height of the cable deflection is adjustable individually.
Moreover, regardless of the concept of the invention mentioned above, it is advantageous if the retaining means, in particular the sole clamping means associated with it, is connected at variable height to the ski or binding or to the casing of the binding. This applies especially to its pivot axis, in cases where the retaining means is pivotably connected to the ski or binding. This permits individual adjustment of the tensioning force, especially the return force by which the retaining means acts on the shoe.
If the retaining means is embodied by a rigid sole plate, the latter preferably is located slightly deeper than the sole supporting surface in the area of the supporting means associated with the front sole section so that, when the shoe heel is raised, the front sole can curve downwardly substantially without obstruction behind the hinge point of the sole plate. Furthermore, With this design the sole is maintained substantially in flat orientation between the metatarsal zone and the heel of the shoe. Between the metatarsal zone and the plantar arch, more specifically, this is accomplished by the rigid sole plate, and between the plantar arch and the shoe heel by the sole and shoe structure proper which is rather rigid here.
Two alternatives should be emphasized as regards the support of the shoe in upward direction. The first alternative is characterized in that the front part of the shoe is supported upwardly only in the range of the forward sole end, in particular directly at the forward sole end. With the other alternative, the supporting means firmly holds the shoe or its sole on the ski or similar sports equipment, starting from the forward sole end approximately up to the metatarsal zone.
As already mentioned above, special attention should be paid to the step-in structure When the binding is in release position, with this design, the tensioning or clamping means of the retaining means is held in a position at which it is swung upwardly by an elastically biased toggle lever mechanism. As one steps into the binding and puts down the shoe, one causes the toggle lever mechanism to adopt a bottom ultra dead center position at which the tensioning or clamping means is shifted to and held in shoe closing position. In a particular embodiment, the toggle lever mechanism is composed of a rear lever extending parallel to the longitudinal direction of the ski and pivotably connected to the ski or binding, and a front lever also extending parallel to the longitudinal direction of the ski and being pivotably connected, on the one hand, to the front end of the rear lever and, on the other hand, to the tensioning or clamping means which is supported for longitudinal displacement. The tensioning or clamping means of the retaining means rests on the front lever of the toggle lever mechanism, preferably on the top of the front lever. With the binding in release position, the two levers of the toggle lever mechanism are angled upwardly, approximately defining a V, so that the hinge connection between the two levers lies above the ultra dead center line. In the bottom ultra dead center position, the hinge connection between the two levers is located below the ultra dead center line. The elastic biasing of the toggle lever mechanism is accomplished by a helical compression spring linked, at one end, to the common hinge connection between the front and rear levers and, at the other end, to a stationary part of the binding or casing of the binding in front of the toggle lever mechanism. In the bottom ultra dead center position, the hinge connection between the two levers is located somewhat less below the ultra dead center line than it is located above the ultra dead center line in the release position of the binding. For this reason the helical compression spring is compressed when in the bottom ultra dead center position, whereby the desired elastic bias is produced. Relief of the bias can be obtained by a simple opening mechanism which acts on the common hinge connection between the two levers while, at the same time, the common hinge connection moves into the top ultra dead center position. The opening mechanism is characterized by an opening means which is coupled to a lever or similar operating member disposed in front of or behind the shoe. Upon actuation of the operating member the toggle lever mechanism thus can be moved out of a bottom ultra dead center position. The opening means, for instance, may include a wedge supported so as to be longitudinally displaceable and having one wedge face which is adapted to be moved against the hinge axis interconnecting the front and rear levers and simultaneously lifts the same to pass the ultra dead center line.